Anytime a thread wants to get access to an item that might be claimed by another thread, it must use a lock to make sure that only one thread at a time can modify the item. Managing multiple threads within an individual program can be a complex task, and poorly written applications can result in an entire application becoming locked as threads wait for each other to finish. Multicore-aware software can be broken up into multiple threads and assigned to each core without slowing down performance.[21] Prior to Windows 7 (July 2009 – January 2015), when a thread needed to get (or access) a lock, its request had to go through a global locking mechanism. This mechanism called the “kernel dispatcher lock” would handle the requests. Because it was unique and global, it handled potentially thousands of requests from all processors on which Windows ran. As a result, this dispatcher lock was becoming a major bottleneck. The Windows 7 operating system had a built-in software called “the scheduler” that was smart about assigning software tasks. The scheduler knew which cores are being used and which cores are busiest. The scheduler then assigned tasks or threads to an unused or under-utilised core. The scheduler also prioritised more important threads or apps as needed. And thanks to built-in tools, programmers could write applications that worked well with multiple cores.[22] [23][24] Earlier versions of Windows desktop graphics weren’t designed for multi-core CPU’s. A program often had to wait until a previous application finished any graphical tasks it needed to perform before it could access the Windows Desktop. With Windows 7, each application communicates with the Windows graphics subsystem, which then manages access to the underlying graphics hardware. Programs no longer have to wait in line. Gaming graphics also got a boost as Microsoft’s programming interface for games, DirectX 11, had been re-engineered to better support multiple CPU cores.[22]>